Musical instruments, especially of the percussion type

ABSTRACT

In application of the invention to a keyboard musical instrument such as a piano, the key is guided by a deformable parallelogram linkage, so that during its actuated displacement, the key remains parallel to its original orientation; between each key and the associated hammer is interposed a transmission which, when the key is depressed, gives the hammer an accelerated movement with respect to the movement of depression of the said key; the release of the transmission for the free return of the hammer after striking is effected after the full depression of the key during the sole inertia movement of the hammer towards the wire; the effect of the soft pedal is obtained by continuous modification of the active length of an intermediate lever of the transmission.

United States Patent Raffali [54] MUSICAL INSTRUMENTS,

ESPECIALLY OF THE PERCUSSION TYPE Inventor: Andre Raffali, 188, Avenue de Verdun, 36 Chateauroux, France Filed: Oct. 9, 1970 Appl. No.: 79,499

Related US. Application Data Division of Ser. No. 761,099, Sept. 20, 1968, Pat. No. 3,559,526.

[30] Foreign Application Priority Data Sept. 25, 1967 France ..67122069 [56] References Cited UNITED STATES PATENTS 8/1888 .Richardson ..84/222 l0/l908 Perry ..84/236 1 Oct. 24, 1972 Primary Examiner-Richard B. Wilkinson Assistant Examiner-Lawrence R. Franklin Attorney-Sandoe, Hopgood & Calimafde ABSI'RACT In application of the invention to a keyboard musical instrument such as a piano, the key is guided by a deformable parallelogram linkage, so that during its actuated displacement, the key remains parallel to its original orientation; between each key and the associated hammer is interposed a transmission which, when the key is depressed, gives the hammer an accelerated movement with respect to the movement of depression of the said key; the release of the transmission for the free return of the hammer after striking is effected after the full depression of the key during the sole inertia movement of the hammer towards the wire; the effect of the soft pedal is obtained by continuous modification of the active length of an intermediate lever of the transmission.

10 Claims, 1 1 Drawing Figures PATENTEDnm m2 SHEET. 1 0F 5 MUSICAL INSTRUMENTS, ESPECIALLY OF THE PERCUSSION TYPE BACKGROUND OF THE INVENTION The present invention relates generally to musical instruments comprising a keyboard with keys, and is more particularly directed to instruments of the percussion type, that is to say instruments such as the piano, for which, with each key of the keyboard there is associated a hammer pivotally mounted between a rest or waiting position and a striking position of a musical device which, in the particular case of the piano, is a wire or set of wires. To this end, between each key and the associated hammer there is interposed an appropriate transmission mechanism for driving the hammer from its position of rest to its striking position when the key itself is depressed from a high position-of rest to a low striking position. All the known instruments of this type have acertain number of disadvantages and inadequacies.

In present-day pianos, and generally speaking in all keyboard instruments such as instruments sold under the commercial name of CLAVIOLINE, harmoniums or the like, each key is carried by a simple lever articulated on the frame of the instrument. This results in a variable hardness of touch, depending on the position of the finger on the key, this hardness increasing when the finger is moved from the front part towards the rear part of the key, that is to say as the finger approaches the articulation point or pivot of the key.

This drawback is particularly marked with short instruments such as upright pianos, in which lack of space limits the length which it is possible to give to the key-carrier levers.

In present-day pianos, the transmission mechanism interposed between a key and its associated hammer is such that the movement relation which it introduces between a depression movement of the key and the corresponding angular movement of the hammer, is substantially linear. Now, as is well known, in order to launch a weight, in the present case that of the hammer, with a constant force, there must be impressed on the hammer an accelerated and nonuniform movement. From the linear coupling ensured by the transmission mechanisms employed at the present time, there results therefore for a performer, a particular hardness when striking a key, followed by a poor control of the hammer, which, impelled too rapidly at the start, is subsequently less sensitive to the action of the key.

In addition, various arrangements are provided in present-day pianos, to comply with particular requirements.

In the first place, the transmission mechanism rest position, reaches a level which, during the depression, corresponds to the intermediate position at which the hammer is waiting. This arrangement makes it possible to re-actuate the hammer immediately before the complete return of the key to its high position of rest, thereby facilitating the execution of repeated notes.

In present-day pianos, this escape of the hammer with respect to its propulsion mechanism is effected during the depression of the key, by abutment and sliding of a member known as a release finger. This results in an additional discontinuity in the hardness of the touch which is particularly troublesome during the execution of soft shades of expression.

Furthermore, in addition to the loud pedal which has the function of cutting out the action of dampers which stop the vibration of the wire or wires of a note when the corresponding key has returned to its high position of rest, present-day pianos are provided with a soft pedal, the purpose of which is to permit of a reduction of the sound intensity emitted when striking a key.

According to a first known arrangement, the soft pedal effect is obtained by laterally displacing all the hammers, so that they only strike one or two wires of the one, two or three wires which compose each note. This arrangement has a two-fold disadvantage: on the one hand, the effect obtained is not uniform over the whole register, since the bass notes in particular, which only have one wire, are not affected, and on the other hand, the effect obtained is much more a hardening of the timber than a reduction of the sound intensity emitted, since the power of the hammers is not modified in any way.

In accordance with a second known arrangement,

the effect of the soft pedal is obtained by modifying the position of rest of the hammers so as to reduce the possible striking travel of the said hammers. This arrangement is more effective than that previously described, but the resulting introduction of a play between the hammers and their propulsion mechanisms causes a discontinuity in the hardness of touch of the keyboard, which gives the player an annoying sensation of floppiness at the beginning of the travel of the keys.

SUMMARY OF THE INVENTION The present invention has for its object a number of improvements which enable the above-mentioned drawbacks to be overcome.

One object of the invention is to provide a keyboard musical instrument in which a key may be struck at any point along its length, without the behavior or the sensitivity of the key being thereby modified.

A further object is to provide an improved key and hammer action which facilitates the execution of certain chords or successions of notes, and in particular of the chromatic glissendo which brings into play successions of alternate black and white keys.

Another object which relates more particularly to during the course of depression of the corresponding key, but after the latter has reached its low striking position.

A further object is to obtain the soft by a continuously variable means.

These and other objects according to the invention are achieved especially by the association of each key of the keyboard of the instrument with a deformable parallelogram linkage such that, during the course of its movements, the key remains parallel to itself; by the arrangement between each key and associated hammer of an accelerating transmission; by the inclusion in this transmission of a release means adapted to permit the free return of the hammer after striking, after complete depression of the key, and during the inertial movement alone of the hammer towards the guardrest; by the arrangement of a soft-pedal means adapted to obpedal effect tain, simultaneously for all the keys of the keyboard, a

continuous modification of the movement ratio obtained by the accelerating transmissions respectively associated with the said keys.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 9 is a diagrammatic view of an alternative form of construction of the accelerating transmission; and

FIG. 10 is a perspective view of the operating mechanism for a soft pedal control-of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the form of embodiment chosen and shown in FIGS. 1 to 3, which concern, by way of example, the application of the invention to a grand piano, any key 10 of the keyboard of this piano is carried by a small pillar 11 mounted for axial displacement between two fixed stops, a lower stop 12 and an upper stop 13. For guiding its movements, the pillar 11 forms one of the sides, known as the driving side, of a deformable parallelogram linkage 14, the opposite side of which is formed by the frame, shown as two fixed members 15A, 15B. The pillar 11 is coupled to the members 15A and 15B by oscillating guiding arms 16A, 16B respectively. According to the form of embodiment shown, the guiding arms 16A and 16B are single flexible blades. As shown, and preferably, the effective spans or lengths of the flexible blades 16A, 16B are the same and are substantially the same as the effective spans or lengths of the fixed link 15A, 15B) and of the movable link (pillar 11); the range of movement of the movable link 11 is constrained by stops (12, 13) to be small compared to the effective spans of all links, and

throughout the range of movement of the pillar link 11, all corner angles of the parallelogram remain substantially.

The pillar 11 also carries a rigid finger 17 parallel to the key 10. This finger is hollowed by an axialbore 18, in which a rod 19 is slidably mounted. For preventing its rotation and driving its sliding movement, which will be detailed later, the rod 19 has a heel 20 engaged in a slot 21 formed longitudinally in the finger 17, at the lower portion of its axial bore 18. The rod 19 has a curved head 22, supported against a lever 23, known as the intermediate lever, on a flat supporting surface 24 of this latter. This intermediate lever 23 is pivoted at 25 on a fixed member 26 and is subjected to the action of a return spring 27, which in turn is coupled at 28 to the frame of the instrument. I

An angle lever or bell crank 30, known as the acceleration lever, is pivoted by its elbow at 31 on an extension 32 of the fixed member 15A;'the bell crank 30 comprises a driven arm 33 and a driving arm 34. A

driving rod or link 36 pivoted to the driven arm 33 connects bell crank 30 to the intermediate lever 23. The length of the driven arm 33 between its pivots 31 and 35 is small as compared with that of the intermediate lever 23 between its pivot 25 and its connection to the rod 36. g

The driving arm 34 pivotally carries at 37 an angle lever or bell crank 38, known as the driving-and-release lever or finger, comprising, on each side of its point of connection to the acceleration lever 30, a return arm 39 (connected by a spring 40 to the intermediate lever 23), and a driving-and-release arm 41.

The hammer assembly 43 for key 10 is pivoted at 42 to the frame member 15A. The hammer assembly comprises an arm 44 and a felt-padded head 45 and is movable about pivot 42 in the direction for head 45 to strike one or more wires, shown diagrammatically by a heavy line 46 in FIGS. 1 to 3. Means, not detailed, permit head 45 to be advantageously fixed at a selected height or offset above arm 44. In its central portion, the arm 44 has a release opening 50 having along one of its edges a notch 51 known as the release notch, positioned for engagement by the free extremity of arm 41 of the driving-and-relea'se lever 38.

On the free extremity of arm 44, and below head 45, is pivoted a lever 52 known as the take-up lever. As can be more clearly seen from FIG. 1A, the small angular movement of this lever, which can take the form of a stirrup engaged to arm 44 (thereby defining a lower terminal edge of arm 44), is limited in each direction by two supporting surfaces 53A and 53B of arm 44. The stirrup 52 extends oblique with respect to the arm 44.

Facing the arm 41 of the driving and release lever 38, the hammer arm 44 carries an oblique arm or abutment 125.

Facing the free extremity of the hammer assembly 43, the intermediate lever 23 carries an upstanding arm 55, the free extremity of which has two successive notches, namely an upper notch 56, known as the takeup notch and a lower or rest notch 57; an inclined surface 58 provides the offset between notches 56 and 57. On the outer side of notch '56, arm 55 carries a projection or braking strip 59 and similarly, on the outer limit of notch 57, arm 55' carries another projection or braking strip 60.

As will have been understood, the intermediate lever 23 forms a driving member for the acceleration lever 30; and the direction of movement of this driving member, or driving direction; perpendicular to the longitudinal axis of the lever 23, has been shown diagrammatically by an arrow D1 in FIG. 1; similarly, the hammer arm 44 forms a receiving member for the acceleration lever 30, and the direction of movement, or receiving direction, perpendicular to the longitudinal axis of arm 44 has been shown diagrammatically by an arrow D2 in FIG. 1.

When the mechanism is in the waiting or rest position, as shown in FIG. 1, the key is in its high position; the pillar 11 is in abutment against the upper stop 13; the driven arm 33 of the acceleration lever 30 forms with the lever 23 an angle which is 0 or near 0 (and which will become a greater acute angle as lever 30 is rocked counter-clockwise); arm 39 of the drivingand-release lever 38 forms with the spring- 40 an upwardly facing obtuse and very open angle; arm 41 of this lever 38 is engaged in the driving notch 51 of the hammer assembly 43 and forms, with the alignment of notch 51 and pivot 42, an angle A substantially equal to 90; the alignment 5142 also forms with arm 34 of lever 30, an angle equal to or slightly less than 90; in the direction toward the free end of the hammer 43; the take-up lever 52 is supported against the face 53A of the hammer and the latter rests by its extremity on the lower notch 57 of arm 55 of the intermediate lever 23.

In practice, as can be seen from FIG. 1, the link 36 and the finger 41 of the lever 38 are approximately and respectively parallel, in the initial or at-rest position, to the driving and receiving directions D1 and D2.

When the key 10 is depressed, it is displaced to the low or striking position, as shown in FIG. 2. During the course of this downward movement, the finger 17 (including its rod ,19) causes the intermediate lever 23 to pivot in the direction of the arrow 75 of FIG. 1. If the depression of the key is approximately uniform, the rotation of the intermediate lever 23, which is substantially proportional to the depression of the key, is also approximately uniform and this is true for the downward movement, namely X,.which results for the driving link 36 to lever 30, the angular movement of link 36 being negligible and involving substantially equal downward movements of its extremities. As the length of the intermediate lever 23 is great, or in any case considerably greater than that, namely R, of the driven arm 33, between the pivots 31 and 35, rotation of lever 23 is negligible with respect to that of the driven arm 33 (and, therefore, of bell crank or lever 30), and is approximately equal to are sin X/R; taking into account the initial conditions specified above, rotation of the driven arm 33 of lever 30 is accelerated with respect to the downward movement X of the driving link 36, and therefore with respect to the depression of the key 10.

During the course of the rotation of the bell crank or acceleration lever 30, arm 41 of the driving and release lever or finger 38, being engaged at notch 51, drives the hammer assembly 43, causing it to rotate in the direction of the arrow 76 of FIG. 1 (i.e., counterclockwise about its pivot 42). As long as arm 34 of lever 30 does not exceed a limiting position in which it is parallel to the alignment 51-42, the resulting hammer movement is one of acceleration, tracking that which has been described for the acceleration lever 30, which, as has been seen, is in turn accelerated with respect to the depressed movement of key 10. As the driving and receiving directions D1 and D2 are only slightly variable (i.e., are substantially opposed), the effects of these two accelerations are additive, and the result is a substantial acceleration of hammer head 45 with-respect to key 10.

The total acceleration obtained is increasingly great as the final position of arm 33 of lever 30 approaches its limiting position, namely a position of alignment with link 36, since the initial position of driving arm 38 is always close to its limit, namely substantially perpendicular to the alignment 42-51. In practice, care is taken not to permit the arm 33 to work too near to itsfinal limiting position, since such a relationship produces excessive acceleration of the hammer and excessive longitudinal force on the driving link 36 and arm 33. I

It is important to note that during the course of the movement of acceleration lever 30, the driven arm 33 of the latter sweeps out an angle equal to or less than between an initial or at-rest position which, in the limit, is perpendicular to the driving direction D1 and a final or actuated position which, in the limit, is parallel to this direction D1 or in alignment therewith. Similarly, during the course of this movement, the driving arm 34 sweeps out an angle equal to or less than 90 between an initial position which, in the limit, is parallel to the receiving direction D2 and a final position which, in the limit, is perpendicular to the said direction D2.

It will be understood that choice of the angle between arms of the bell crank or lever 30 will depend on the relative angle between the driving direction D1 and the receiving direction D2; since in the form disclosed, directions D1 and D2 are substantially opposite, the bell-crank arm angle is substantially 90 degrees.

During the course of rotation of lever 30 to lift the driving-and-release lever 38, the obtuse angle formed between arm 39 and the return spring 40 becomes reversed, whereupon lever 38 is urged in the direction for which its arm 41 tends to escape from the driving notch 51 of the hammer 43. As long as key 10 is being driven down, arm 41 is maintained in frictional engagement with the notch 51, but when key drive ceases, the reversed spring action disengages arm 41 from notch 51 (see FIG. 2), as will be more fully explained.

When key 10 reaches its bottom striking position (abutment 12), the hammer head 45 is close to its actual striking position but is in fact slightly short of this position. It is, thus, freely and by simple inertia (momentum) that the hammer assembly 43- strikes the wire or wires 40. During the course of this free travel, friction contact is interrupted between notch 51 and arm 41; at the same time, abutment arm of the hammer assembly 43 comes into striking contact with arm 41. Lever 38 then pivots towards the release opening 50, aided by the action of return spring 40, so that when the hammer assembly 43, after striking the wire or wires 46, retracts by rebound (aided, as by a return spring, not shown, or by gravity, in the example shown), the hammer notch 51 escapes from arm 41 of by friction on the braking strip 59, it being understood that, during the downward movement of key 10, the

braking strip 59 followed the counterclockwise move ment of member 55 towards hammer pivot- 42. The

' elastic damping effect of strip 59 prevents further rebounding of the hammer. In FIG. 2, the braked position of the hammer has been shown in full lines, and the striking position of the hammer is shown in phantom.

It should be observed that the escape of lever 38 takes place after key 10 has reached its low or striking position.

During the striking action of the hammer, the takeup lever 52-remains withdrawn under the hammer 45 head supported against the surface 53A, and does not engage the notch 56.

If key 10 is nowpermitted to return to its high position of rest, by the-action of spring 27, the braking strip 59 moves away from and releases the hammer assembly 43, which continues to drop until its take-up lever 52 is supported by the take-up notch 56 of arm 55. From this moment, and if upward movement of the key 10 continues, take-up lever 52 pivots while supported on the notch 56, transferring its abutment from surface 53A to surface 53B to retain the hammer assembly 43 in the position shown in FIG. 3, known as the intermediate position, while the remainder of the mechanism tends to return gradually to its initial position. During the course of this return movement, the obtuse angle of arm 39 of lever 38 with the associated retumspring 40 reverses again to resume its initial orientation, so that arm 41 of lever 38 (as it moves down) may return to engage the hammer notch 51, just before notch 56 withdraws under the take-up lever 52 and liberates the latter.

The driving coupling between key 10 and the hammer assembly 43 is thus restored at a position of this key, shown (by clearance with stop 12) in FIG. 3, intermediate between its low striking position and its high rest position. It is thus possible by depressing key 10 to strike the wire or wires 41 again before the key has returned to its high position. It is also possible to permit key 10 to return to its high rest position (FIG. 1) by the action of spring 27. The final drop of the hammer onto the notch surface 57 is damped by the flexible braking strip 60 which rubs against the end or heel portion of the hammer arm 43.

In accordance with the invention, the soft pedal" effect is obtained by continuous reduction of the ratio of movement between the key-10 and the hammer 43; in practice, following the example shown, this reduction is obtained by modifying the active length of the intermediate lever 23 (i.e., operative radial distance) between pivot 25 and the point of engagement with rod 19, that is to say, by displacing rod 19 inside the finger 17. This displacement modifies the rest position of the intermediate lever 23 and therefore that of the hammer assemble 43, without modifying the striking position of the hammer; in fact, the arrangement according to the invention is such that forthe striking position of lever 23 (see FIG. 2), the supporting surface 24 of this latter, on which the head 22 of the rod 19 bears, is preferably parallel to finger 17 and therefore to the sliding axis of rod 19.

If rod 19 is actuated by sliding towards the left of FIG. '1, the at-rest position of intermediate lever 23 pivots in the direction of the arrow 75, and in consequence the hammer assembly pivots in the direction of the arrow 76. The new at-rest position of the hammer will therefore be nearer to the striking position than the previous position. The possible travel of the hammer and its speed relative to that of the key being then reduced, it will strike the wire 46 with a lower power, other conditions being equal; in consequence, the sound intensity will be reduced, which is of course the effect desired.

The sliding movement of rod 19 can, for example, be effected by a device of the type shown in FIG. 10. The heel 20 of the rod 19 is engaged in the slot 80 of a comb 81 common to all or to at least a plurality of adjacent heels 20. This comb is carried by two like end-plates or bell cranks 82A, 82B pivotally carried by the frame of the instrument, and the end-plates 82A, 82B conjointly carry a cross-member 83 which, in turn, is connected by a rod 84 to the soft pedal 85. When the soft pedal is depressed, the comb 81 rocks in the direction of the arrow 86 and drives the heels 20 in the direction, as explained above, corresponding as desired to a reduction of the sound intensity emitted when striking a note.

FIGS. 4 to 7 illustrate various alternative forms relative to the deformable parallelogram guiding device for key 10.

According to the alternative form shown in FIG. 4, the oscillating guiding arms of this parallelogram are rigid links 66A, 66B, connected at their extremities by pivots 67, on the one hand on the driving side 11 of the parallelogram and on the other hand to the fixed or frame-based side 15 thereof.

The alternative shown in FIG. 5 concerns the case in which, as previously (FIG. 1) these guiding arms are flexible blades which have the advantage of eliminating the causes of wear and maladjustment of the parallelogram which theyv form. These flexible blades must of course be sufficiently rigid to be able to withstand longitudinal compression forces, that is to say should be resistant to buckling. Now, due'to the direction of action of the finger on key 10, the weight of this key and the inertia and restoring force of the mechanism which it drives, the upper oscillating blade 16A (not shown in FIG. 5) always works in tension, while the lower oscillating blade 16B always works in compression. Under these conditions, it can be advantageous to associate shown diagrammatically in FIG. 5.

In the alternative form of FIG. 6, the lower oscillating arm may be a rigid blade 68, having its pointed extremities 69, supported in the bottom of grooves 71,72 formed respectively in the driving side 11 of the deformable parallelogram and in the fixed side 15 of this latter.

Up to this point, it has been assumed that key 10 was fixed to a flank of the driving side 11 opposite to that on which the oscillating guiding arms 16A, 16B are fixed. According to the alternative construction shown in FIG. 7, which is particularly suitable for keyboard instruments of smalldimensions, key 10 is arranged on the same side as the guiding arms with respect to the driving side 11 of the parallelogram. For example, as shown, key 10 is arranged above this parallelogram. An

intermediate position of the key on the driving side, extending on each side beyond this latter, is also possible. In this case, each oscillating arm is capable of working in tension or in compression, depending on the striking position of the finger on the key. The free space between the oscillating arms 16A, 163 can be employed for the reception of various members of the instrument and especially for the reception of members appropriate to each key or note. If this space remains unused, it can be reduced by bringing the oscillating arms 16A, 16B closer to each other within the limits of the longitudinal forces which the arms are capable of withstanding without deformation.

FIG. 8 illustrates by way of example a fresh possibility of arrangement of the keyboard, permitted by the method of guiding utilized according to the invention for thewhite keys 10 of this keyboard, together with the associated black keys 10A. Each key 10 has at its rear portion a section 108 which, raised above the remainder of the white key considered, is level with the adjacent black keys 10A and is engaged between these latter. The keyboard is thus provided advantageously with a zone Z in which the black and white keys have the same level and the same width, this zone being particularly adapted for the execution of the chromatic glissando.

According to an alternative form (not shown), the rear portions 108 of the white keys have a zone, behind the black keys, which is raised with respect to the black keys.

FIG. 9 relates to an alternative form of accelerating transmission. Two arms 90, 91 are mounted in contact with each other by two cylindrical surfaces of appropriate divergent profiles 92, 93 respectively, at least one of the surfaces being convex, while the other is convex, concave or flat. In the example shown, the surfaces 92, 93 are both convex. The arms 90, 91 are rotatably mounted on pivots 94, 95 respectively, parallel to the generator lines of the surfaces 92, 9.3 and at a distance from these latter.

When the arm 90 pivots about its axis 94 in the direction of the arrow 96, the contact generator 97 of thetwo arms moves away from the pivot 94 and approaches the pivot 95, and the rotation of the arm 91 is thus accelerated following the relative curvature of the surfaces 92, 93.

According to an alternative construction (not shown), one of the arms 90, 91 is guided in a parallel translation movement instead of being pivoted. In the same way, by displacement of the contact generator line, the movement of one lever towards the other communicates an accelerated movement.

The transmission mechanism according to the invention which has been described and shown, by way of example, with reference ,to grand pianos, can readily be adapted to upright pianos, for example by conversion of the vertical movement of a key to a horizontal movement for the driving side of the associated deformable parallelogram.

Thus, adaptation of the mechanism shown in FIG. 1

to an upright piano is effected by fixing finger 17, not to the pillar 11, but vertically on the lower oscillating arm 168 on the side of the member 158. This oscillating arm is rigid according to any one of the forms of construction described above with reference to FIGS. 4,

and 6, such a finger (corresponding to 17 in FIG. 1) being suggested at 660 in FIG. 4. This oscillating arm thus forms with the finger 17 (660) a square which transmits the downwardmovement of the key. With respect to the wires, which are vertical in an upright piano, the remainder of the mechanism occupies the same position as that shown in FIG. 1. Thus, rod 19 is engaged vertically in finger 17, its heel 20 being directed horizontally towards the keyboard. The finger l7 and rod 19 are in this case guided in rotation instead of being guided in parallel movement; this modifies slightly the conditions of operation but not the principle of the system. The dampers which, in the upright piano, are located on the same side as the hammers with respect to the wires, can be actuated directly by takingoff the movement from the finger 17 or from the lever 23.

In .the present description, no mention has been made of the various adjustment devices which may be rendered necessary by the wear of parts in frictional contact and the degree of precision of manufacture.

- These adjustments mainly concern the supporting surface of lever 23, notch 51 and finger 12 5 of the hammer, and also the position of flexible blade 59 on arm 55. Also, no mention has been made of the nature of the friction or contact surfaces. These problems can be resolved by following the techniques usually employed in the art.

It will of course be understood that the present invention is not limited to the forms of embodiment described and shown, but includes all alternative forms of construction or combination of their various parts.

What I claim is:

l. A keyboard musical instrument of the percussion type comprising a plurality of keys and, associated with each of said keys, a hammer pivotally mounted between a position of rest and a striking position, a transmission interposed between said keys and said hammers, said transmission comprising an acceleration lever adapted to transmit to said hammers a striking movement which is accelerated with respect to the downward movement impressed on the corresponding key, said lever comprising a bell crank with a driven arm and a driving arm on each side of a fixed pivot axis, a driving member adapted to transmit the movement of the key to said driven arm, and a receiving member adapted to transmit the movement of said driving arm to said hammer.

2. A musical instrument according to claim 1, in which said transmission further includes an actuating connection for said driving member including longitudinally telescoping members between the key and said driving member, and an expression-control connection to one of said telescoping members for adjustably controlling the connection of the key to its accelerating lever, whereby expression control is achieved.

3. A musical instrument as claimed in claim 1, in which, to the downward movement of a key there corresponds, for said driven arm of said acceleration lever, an orientation with respect to the direction of movement of said driving member, which varies from an orientation close to the perpendicular to an orientation close to parallel.

4. A musical instrument as claimed in claim 1, comprising a soft pedal, in which said transmission associated with each of said keys further comprises an intermediate lever and adjustably variable means adapted to modify the active length of said intermediate lever, said soft pedal being connected in adjustive relation with said variable means to act simultaneously on said variation means of all said transmissions.

5. A musical instrument as claimed in claim 1, in which, for the control of the hammer, a driving and release finger is pivotally carried on said driving arm of said acceleration lever, said driving arm forming with the straight line joining the point of articulation of the hammer and the common point of said hammer and said driving finger, an angle which varies during the course of the downward movement of the key, from a value close to the perpendicular to a value in the vicinity of 0.

6. A musical instrument as claimed in claim 5, in which said driving-and-release finger associated with each of said hammers 'for controlling the same, comprises a bell crank lever pivotally carried by said driving arm including a return arm and a driving-and-release arm, said transmission further comprising elastic restoring means adapted to act on said return arm and a driving notch formed'on said hammer, said driving and release arm being supported on said notch in the position of rest of the hammer.

7. A musical instrument as claimed in claim 6, in which said elastic restoring means comprises an elongated spring forming with said return arm of said driving and release arm, in the position of rest of the key, an angle such that said driving and release arm is kept applied against said driving notch of the hammer and such that, while in the striking position of the key, said angle is reversed so that said driving and release arm is urged by said restoring spring in a direction tending to cause it to be released from the driving notch of said hammer.

8. A musicalinstrument as claimed in claim 6, in which said hammer is adapted, in the striking position of the key, to occupy a position located short of its striking position and comprises an inclined arm or stud which, for said striking position of the key, comes into contact with the associated driving and release finger and causes the release of this finger in the phase of movement of the hammer comprised between the striking position of the key and the striking position of the hammer.

9. A musical instrument as claimed in claim 8, in which each hammer comprises, on a terminal portion, a take-up lever oscillatably mounted between two extreme positions, and said intermediate lever comprises a take-up notch with which said take-up lever is adapted to come into engagement while, after its depression, said key returns to its high position of rest so as to maintain thehammer in an intermediate waiting position during a first phase of the upward movement of the key, beyond which upward movement phase said driving and release arm again comes into contact under said notch of the hammer, following the mode of operation known as double release.

10. A musical instrument as claimed in claim 9, in which said intermediate lever comprises, on each side of said take-up notch, an oblique friction surface and an obli ue lane terrni atin at a su ortin s rface for the hariimei at rest, saia sup%)orting si i rfaceam i ng parallel to said take-up notch. 

1. A keyboard musical instrument of the percussion type comprising a plurality of keys and, associated with each of said keys, a hammer pivotally mounted between a position of rest and a striking position, a transmission interposed between said keys and said hammers, said transmission comprising an acceleration lever adapted to transmit to said hammers a striking movement which is accelerated with respect to the downward movement impressed on the corresponding key, said lever comprising a bell crank with a driven arm and a driving arm on each side of a fixed pivot axis, a driving member adapted to transmit the movement of the key to said driven arm, and a receiving member adapted to transmit the movement of said driving arm to said hammer.
 2. A musical instrument according to claim 1, in which said transmission further includes an actuating connection for said driving member including longitudinally telescoping members between the key and said driving member, and an expression-control connection to one of said telescoping members for adjustably controlling the connection of the key to its accelerating lever, whereby expression control is achieved.
 3. A musical instrument as claimed in claim 1, in which, to the downward movement of a key there corresponds, for said driven arm of said acceleration lever, an orientation with respect to the direction of movement of said driving member, which varies from an orientation close to the perpendicular to an orientation close to parallel.
 4. A musical instrument as claimed in claim 1, comprising a soft pedal, in which said transmission associated with each of said keys further comprises an intermediate lever and adjustably variable means adapted to modify the active length of said intermediate lever, said soft pedal being connected in adjustive relation with said variable means to act simultaneously on said variation means of all said transmissions.
 5. A musical instrument as claimed in claim 1, in which, for the control of the hammer, a driving and release finger is pivotally carried on said driving arm of said acceleration lever, said driving arm forming with the straight line joining the point of articulation of the hammer and the common point of said hammer and said driving finger, an angle which varies during the course of the downward movement of the key, from a value close to the perpendicular to a value in the vicinity of
 0. 6. A musical instrument as claimed in claim 5, in which said driving-and-release finger associated with each of said hammers for controlling the same, comprises a bell crank lever pivotally carried by said driving arm including a return arm and a driving-and-release arm, said transmission further comprising elastic restoring means adapted to act on said return arm and a driving notch formed on said hammer, said driving and release arm being supported on said notch in the position of rest of the hammer.
 7. A musical instrument as claimed in claim 6, in which said elastic restOring means comprises an elongated spring forming with said return arm of said driving and release arm, in the position of rest of the key, an angle such that said driving and release arm is kept applied against said driving notch of the hammer and such that, while in the striking position of the key, said angle is reversed so that said driving and release arm is urged by said restoring spring in a direction tending to cause it to be released from the driving notch of said hammer.
 8. A musical instrument as claimed in claim 6, in which said hammer is adapted, in the striking position of the key, to occupy a position located short of its striking position and comprises an inclined arm or stud which, for said striking position of the key, comes into contact with the associated driving and release finger and causes the release of this finger in the phase of movement of the hammer comprised between the striking position of the key and the striking position of the hammer.
 9. A musical instrument as claimed in claim 8, in which each hammer comprises, on a terminal portion, a take-up lever oscillatably mounted between two extreme positions, and said intermediate lever comprises a take-up notch with which said take-up lever is adapted to come into engagement while, after its depression, said key returns to its high position of rest so as to maintain the hammer in an intermediate waiting position during a first phase of the upward movement of the key, beyond which upward movement phase said driving and release arm again comes into contact under said notch of the hammer, following the mode of operation known as ''''double release.''''
 10. A musical instrument as claimed in claim 9, in which said intermediate lever comprises, on each side of said take-up notch, an oblique friction surface and an oblique plane terminating at a supporting surface for the hammer at rest, said supporting surface being parallel to said take-up notch. 